Technical Field
The present invention relates to filtering undesirable particulates from hydrocarbon production at a subterranean location in a well. In the industry, this field is sometimes referred to as “sand control.”
Background Art
Screens and gravel packing are commonly used as a sand-control method to prevent production of formation sand or other fines from a poorly consolidated subterranean formation. In this context, “fines” are tiny particles that have a tendency to flow through the formation with the production of hydrocarbon. The fines have a tendency to plug small pore spaces in the formation and block the flow of oil. As all the hydrocarbon is flowing from a relatively large region around the wellbore toward a relatively small area around the wellbore, the fines have a tendency to become densely packed and screen out or plug the area immediately around the wellbore. Moreover, the fines are highly abrasive and can be damaging to pumping and oilfield other equipment and operations.
In one common type of gravel packing, a mechanical screen is placed in the wellbore and the surrounding annulus is packed with a particulate of a larger specific size designed to prevent the passage of formation sand or other fines.
For sand control applications screens assemblies of various sizes and shapes are used either alone or surrounding by a gravel pack. In a common application configuration a perforated pipe with screen material is connected to a production string installed in the well. Fine gravel material will be flowed (packed) around the screen causing hydrocarbon production to first flow through the gravel pack and then the screen before entering the perforated pipe of the production string.
While these prior filter systems function adequately they can be damaged during installation and use. In addition, problems are encountered with this type of gravel packing in controlling the distribution of particulate around the screen. When voids are present in the gravel pack, the unprotected areas of the screen at the void can be damaged or the area screened out by excessive flow.